PCIe/PXIe-6301 Series |
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4.2.2
ADC Timing Modes
The ADC Timing Mode uses the built-in digital filters to reduce the measurement noise.
The ADC Timing mode affects the data output rate and 50 Hz / 60 Hz noise rejection.
The lower the ADC conversion rate, the better the noise rejection.
The PCIe/PXIe-6301 driver provides a total of 6 ADC convesrion rates, from Level 0 to
Level 5. Level 0 has the slowest conversion rate and best noise rejection. Level 5 has
the fastest conversion rate and worst noise suppression performance.
The reciprocal of the ADC conversion rate is the time required for each A/D conversion.
Table 15 A/D conversion time at different speed levels
In the default configuration, the conversion rate level is set to Auto, and the drive will
automatically select the lowest possible rate level according to the sampling rate and
the number of added channels. If the user explicitly configures the rate level, the driver
will automatically limit the highest sampling rate according to the number of added
channels and the rate level. If the user-set sampling rate exceeds the limit, the driver
will adjust it to nearest rate level. The conversion rate is set to the maximum possible.
For a more detailed description of the relationship between Timing Modes and
sampling rates, please refer to Section 4.2.3.
4.2.3
Sampling Rate
When PCIe/PXIe-6301 works, each sample contains the completion of an A/D
converter (Convert) on all channels, the principle is as in Figure 13.
ADC Timing Modes
single conversion rate
Single A/D conversion time
Level 0
2.3 Hz
434.7826 ms
Level 1
5.1 H z
196 .0784 ms
Level 2
26.5 Hz
37.7358 ms
Level 3
41 Hz
24.3902 ms
Level 4
410 Hz
2.4390 ms
Level 5
830 Hz
1.1205 ms
